1. Field of the Invention
The present invention generally relates to a mirror structure and a projection apparatus. More particularly, the present invention relates to a mirror structure and a projection apparatus using the same.
2. Description of Related Art
With the development of technology, different kinds of projection apparatuses are widely used in various circumstances. Projection apparatuses are display apparatuses for generating images with large size. The image of the projection apparatus is produced by using a light valve to convert an illumination beam generated by a light source module into an image beam and a lens module to project the image beam onto a screen or a wall. With advancing of the projecting technology and reducing of fabrication cost, the digital light processing projector (DLP projector) is being widely used.
In a conventional digital light processing (DLP) projector, a key component called “digital mirror device” (DMD) is the fundamental semiconductor component. The chip of the digital mirror device is adopted for controlling the digital optical switch by rapidly and precisely reflecting the light source. Unlike the conventional liquid crystal projector that modulates the light by using liquid crystal (LCD) to change the polarization state, DLP projector uses the reflection of micro mirrors to modulate the light. Therefore, the weight of the DLP projector may be reduced to 2.5 kg or less, compared with 8 to 15 kg of a conventional projector. In addition, the volume of the DLP projector can also be minimized. In general, the optical efficiency and contrast of the DLP projector is better than that of the conventional projector, since the digital mirror device uses non-polarized light and switches light by mirrors. Therefore, the DLP projector can be used when high brightness and high resolution is required. In addition, the image reproduced from the DLP projector is a real and stable digital image with correct colors.
However, as the demand of the display quality and the magnifying power of the image increase gradually, the size of the optical engine of the projection apparatus is also increased. For this reason, the size of the projection apparatus is also increased, and this conflicts with the purpose of weight lightening and size minimizing of the DLP projectors. Therefore, to develop a more compact optical engine while maintain the display quality is an important topic in the industry of projection apparatus.